368
METALLURGY OF IRON AND STEEL.
PART II.
EFFECT OF CERTAIN ELEMENTS AS DETERMINED BY SPECIAL MATHEMATICAL INVESTIGATIONS.
SEC. XVIIk.—Investigations ly Webster.—A comprehensive study of the physical formula of steel has been carried out by W. R. Webster.* He has used the laborious method of successive approximations, and by "cutting and trying" has found the effect of each element upon the ultimate strength, as well as the effect of the thickness and finishing temperature. The results are given by him as follows:
.01 per cent, of sulphur increases the tensile strength 500 pounds per square inch.
.01 per cent, of manganese has an effect which varies with each increment as follows, the values being expressed in pounds per square inch:
An. Increase In percentage gives an increment of making a total increase in strength over metal with no manganese of
from. .00 to .15 8600 8600
" .15 to .20 1200 4800
" .20 to £5 1100 5900
" .25 to .80 1000 6900
" .80 to .85 900 7800
" .85 to .40 800 8600
" .40 to .45 700 0300
41 .45 to .50 600 9900
" .50 to .55 500 10400
« .55 to .60 500 10900
» .60 to .65 500 11400
.01 per cent, of phosphorus has an effect which varies according to the amount of carbon present:
With .08 p(er cent, of carbon it is 800 pounds per square inch.
in it ii ^
.10
.11 " "
.12 " "
.13 " «
,14 " "
.15 " "
.16 " »
.17
1000 1100 1200 1300 1400 1500 1500
1500
Carbon has a constant effect of 800 pounds for each .01 per cent.
SEC. XVIII.—The value of carbon, manganese, phosphorus and
iron iii open-hearth, steel as found ly the method of least squares.
* Observations on the Relations between the Chemical Constitution and Physical Char~ acter of Steel. Trans. A. I. M..E., Yol. XXI, p. 766, and Yol. XXIII, p. 113; also Joi^nal I. and S. I., Yol. 1,1894, p. 328.